f The Enhancement of a Crustal Conductive Anomaly in the Southeastern Paraná Basin by Vertical and Impedance Transfer Functions

Electromagnetic data from seventeen sites located at the southeastern border of the Parana Basin, in Santa Catarina and Rio Grande do Sui states, were analyzed for lateral and vertical conductivity variations as a function of frequency. Magnetotelluric (MT) soundings were carried out with a five component single-station equipment which operates in the period range of 0.0006 to 2048 s. The surficial geological setting of the study area includes sedimentary units from the Permian/Carboniferous (Itarare Group) to the Cretaceous (Serra Geral Formation), laying along a NW-SE broad trough (Torres Syncline). The sedimentary evolution and related magmatic events (basalts and alkaline volcanics) were strongly controlled by the NW-SE structures (Rio Uruguay and Torres-Posadas Lineaments and Torres Syncline) during the Phanerozoic. Yet, the Precambrian basement presents a tectonic grain in the orthogonal NE-SW direction, imprinted by a Brasiliano remobilization (Dom Feliciano Foldbelt).